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PHOTOLYSIS AND PHOTO‐OXIDATION OF AMINO ACIDS AND PEPTIDES—IV. THE DEGRADATION OF METHIONINE AND HOMOCYSTINE BY VARIOUS FORMS OF RADIATION
Author(s) -
Forbes W. F.,
Rivett D. E.,
Savige W. E.
Publication year - 1962
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1962.tb08095.x
Subject(s) - methionine , irradiation , chemistry , radical , photochemistry , methionine sulfoxide , ionizing radiation , cystine , aqueous solution , amino acid , degradation (telecommunications) , photodissociation , biochemistry , organic chemistry , cysteine , enzyme , physics , nuclear physics , telecommunications , computer science
Summary The products obtained on irradiation of dilute aqueous solutions of homocystine with either sunlight, related light sources, with 2537Å light, or on irradiation with ionising radiation are mainly different from those obtained for methionine under similar conditions. The degradation products obtained from homocystine and methionine in most cases correspond to those previously obtained from the lower homologues, i.e. cystine and S‐methylcysteine respectively. The initial reaction in the degradation of homocystine, like that of systine, involves both S‐C bond and S‐S bond fission, at least in neutra lor alkaline solution. Solid homocystine and methionine are scarcely affected by sunlight or ionising radiation, but more extensive degradation occurs on irradiation with 2537A light. Both compounds yield ESR signals, indicating the presence of trapped radicals on irradiation in the solid state.